1. Field of the Invention
The present invention relates to a novel radioactive seed sorter and method for sorting radioactive seeds as used primarily in the medical field.
2. Prior Art
Various seed sorting apparatus has been advanced for the purpose of sorting radioactive seeds as used primarily in the medical field. However, such apparatuses as have been advanced, are particularly cumbersome and do not sort the seeds effectively into a number of dose categories in an efficacious manner. Therefore, a need still exists in the art to provide an apparatus and method that works more effectively and efficaciously to this end.
The object and purpose of the present invention is to provide an apparatus and method for sorting radioactive seeds into a number of dose categories in a more efficient and efficacious manner than has heretofore been proposed. This is accomplished by the present invention by providing an apparatus and method that utilizes a dose calibrator with special flow-through ionization chamber, a vibratory feeder bowl for feeding radioactive seeds, a mechanical system to singulate, arrange the fed seeds serially one at a time in end-to-end juxtaposition, and to transport the seeds from the feeder bowl through the dose calibrator, and deposit the seed into an appropriate pig in a sorting table. The sorting table (turret wheel) is positioned to present the proper pig to receive the seed, based on its activity. Electronic detectors are provided at particular locations to monitor the transport of seeds through the system, and to position the moving components of the system, and to provide operator safety, and limited containment.
The present invention concerns apparatus for assaying and sorting radioactive seeds comprising a seed feeder having an outlet to feed seeds out the outlet in line horizontally in end to end fashion; a curved track having a horizontal inlet coupled to the outlet of the seed feeder and having a vertical outlet so seeds can drop by gravity out the vertical outlet; an escapement slide having a first cavity to receive a seed positioned below the vertical outlet of the curved track, the escapement slide reciprocating between a first position where the first cavity is in vertical alignment with the vertical outlet of the curved track and a second position where the slide has been shifted horizontally; a shuttle loader located at the second position of the slide comprised of a vertically oriented loader pin arranged for reciprocating vertical movement between a retracted position and a loading position, with the loader pin in vertical alignment with the first cavity of the slide when it is in the second position; a shuttle located below the slide and arranged to move horizontally from a first retracted position, to an intermediate position and to an unloader position, the shuttle having a second cavity that is in vertical alignment with the loader pin when the shuttle is in the first retracted position; a dose calibrator in alignment horizontally with the shuttle to receive the shuttle in its intermediate position and determine the activity of a seed contained in the second cavity, and to allow the shuttle to pass through when moved to the unloader position; a bridge supporting the shuttle and extending from the first retracted position to the unloader position and defining a hole that is vertically aligned with the shuttle second cavity when the shuttle is in the unloader position to allow a seed in the shuttle to drop through the hole by gravity; a sort table having a series of concentrically mounted receptacles, the sort table capable of being positioned with any one of the receptacles vertically below the hole in the bridge to receive a seed dropping through the hole by gravity; and a processor coupled to the dose calibrator and sort table to process the activity determined by the dose calibrator and to instruct the sort table to position a preselected receptacle beneath the hole in the bridge to receive the seed whose activity was determined.
In addition, the invention can have one or more of the following features. The apparatus for assaying and sorting radioactive seeds includes the curved track having a vertical terminal portion and a sensor is associated with the curved track to determine the presence of seeds to a predetermined level in the vertical terminal portion of the curved track. Also, a sensor is associated with each of the first cavity and second cavity, each sensor determining the presence of a seed respectively associated cavity. Piston-cylinder assemblies are provided coupled to drive the slide and shuttle. Sensors are associated with the piston-cylinder assemblies to control the actuation thereof. The bridge has a cutout at the location corresponding to the intermediate position of the shuttle. The dose calibrator is of annular configuration. The feeder includes a track leading to the feeder outlet with the track having a cutout adjacent to the outlet and an air assist is provided to cooperate with the feeder in the vicinity of the outlet to maintain seeds in a single line. An air assist is provided to cooperate with the curved track. An air jet is positioned over the hole defined in the bridge.
Still further, the invention provides a method for assaying and sorting radioactive seeds comprising the steps of: feeding seeds in line horizontally in end to end fashion; translating the seeds from the horizontal to a vertical stack; singulating the seeds from the vertical stack and moving a singulated seed to a horizontally displaced position; loading the horizontally displaced singulated seed into a shuttle by pushing vertically downward into a cavity in the shuttle; moving the shuttle horizontally from a retracted position where it receives a singulated seed, into one end of an annular dose calibrator to an intermediate position within the dose calibrator and out of the other end of the annular dose calibrator to an unloader position; determining the activity of the singulated seed contained in the cavity while it is in the intermediate position; dropping the singulated seed into one of a plurality of receptacles at the unloader position; and controlling the plurality of receptacles to position a preselected receptacle to receive the singulated seed based on the activity determined.
The method for assaying and sorting radioactive seeds according to the invention can include the further step of sensing the presence of seeds in the vertical stack; the further steps of sensing a seed when initially singulated and sensing a singulated seed in the shuttle; the steps of driving the initially singulated seed to the horizontally displaced position and driving the shuttle between its positions; the further step of controlling the driving of the initially singulated seed and shuttle; the further step of supporting the shuttle at the intermediate position with a reduced section; the step of blowing air into the seeds during translation from the horizontal to the vertical; the further step of blowing air at the seeds to assist in maintaining the horizontal in line feeding of seeds; the further step of blowing air toward the singulated seed to assist in the step of dropping the singulated seed into a receptacle; and the further step of sensing the dropping of a singulated seed into a receptacle.
Other and further objects and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention when taken in conjunction with the appended drawings.